The Internet, like so many other high tech developments, grew from research originally performed by the United States Department of Defense. In the 1960s, the military had accumulated a large collection of incompatible computer networks. Computers on these different networks could not communicate with other computers across their network boundaries.
In the 1960s, the Defense Department wanted to develop a communication system that would permit communication between these different computer networks. Recognizing that a single, centralized communication system would be vulnerable to attacks or sabotage, the Defense Department required that the communication system be decentralized with no critical services concentrated in vulnerable failure points. In order to achieve this goal, the Defense Department established a decentralized standard communication protocol for communication between their computer networks.
A few years later, the National Science Foundation (NSF) wanted to facilitate communication between incompatible network computers at various research institutions across the country. The NSF adopted the Defense Department's protocol for communication, and this combination of research computer networks would eventually evolve into the Internet.
Internet Protocols
The Defense Department's communication protocol governing data transmission between different networks was called the Internet Protocol (IP) standard. The IP standard has been widely adopted for the transmission of discrete information packets across network boundaries. In fact, the IP standard is the standard protocol governing communications between computers and networks on the Internet.
The IP standard identifies the types of services to be provided to users and specifies the mechanisms needed to support these services. The IP standard also specifies the upper and lower system interfaces, defines the services to be provided on these interfaces, and outlines the execution environment for services needed in the system.
In a typical Internet-based communication scenario, data is transmitted from an originating communication device on a first network across a transmission medium to a destination communication device on a second network. After receipt at the second network, the packet is routed through the network to a destination communication device using standard addressing and routing protocols. Because of the standard protocols in Internet communications, the IP protocol on the destination communication device decodes the transmitted information into the original information transmitted by the originating device.
The IP-Based Mobility System
The Internet protocols were originally developed with an assumption that Internet users would be connected to a single, fixed network. With the advent of cellular wireless communication systems using mobile communication devices, the movement of Internet users within a network and across network boundaries has become common. Because of this highly mobile Internet usage, the implicit design assumption of the Internet protocols (e.g. a fixed user location) is violated by the mobility of the user.
In an IP-based mobile communication system, the mobile communication device (e.g. cellular phone, pager, computer, etc.) can be called a mobile node or mobile station. Typically, a mobile station maintains connectivity to its home network while operating on a visited network. The mobile station will always be associated with its home network for IP addressing purposes and will have information routed to it by routers located on the home and visited networks.
Packet-Based Communication Systems
In Internet Protocol (IP) networks, the communication process is very different from prior conventional telecommunication systems. In an IP network communication, there is no open switched connection established between the caller and recipient devices. The information being transmitted between the caller and recipient devices is broken into packets of data, and each packet of data is transmitted to the recipient device in pieces. The data packets individually contain routing information to direct each packet to the recipient device. These packets are then reassembled into a coherent stream of data at the recipient device.
The 3rd Generation Partnership Project 2 (3GPP2), also referred to as CDMA2000, is an evolving third generation communication system standard for wireless communication systems transmitting multimedia services using the packet-based Internet protocol. These 3GPP2 mobile communication systems support multimedia telecommunication services delivering voice (VoIP) and data, to include pictures, video communications, and other multimedia information over mobile wireless connections. These systems generally operate over a derivative General Packet Radio Service (GPRS) and/or Universal Mobile Telecommunication Systems (UMTS) communication system architecture.
During operation, the Mobile Station (MS) can enter an Idle state. That is, the MS alternates between active mode (MS in Traffic Channel state) and dormant mode (MS in Idle state) to save battery power because the packet data applications communicate in a bursty fashion. While in Idle state, the MS monitors a forward link common channel to update configuration related parameters and to receive page or other common channel messages. When in Idle state, the MS can reduce its power consumption by using a slotted mode of operation. In slotted mode, the MS only receives message in pre-determined time slots, so the MS only “wakes up” at these pre-determined times, or time slots, to receive messages on the forward link channel. So the MS usually stops monitoring the forward link common channel when it is not in the pre-determined time slots to save battery power and periodically starts monitoring according to the assigned time slots to receive forward link common channel signaling messages.
Packet data applications may require the MS to monitor the communication channels more frequently while in Idle state, compared to other communication applications, to allow the MS to switch from Idle state to Traffic Channel state faster. When in the Idle state, there is no traffic channel where data packets are transmitted over a communication link in a communication session. When the MS detects a signaling message for an incoming communication, it can exit the Idle state and enter a Traffic state setting up a traffic channel and switching into an active mode for communication very fast.
The existing time slot allocations can result in excessive latency and delay for specific services, so a shorter slot cycle can be specified to “wake up” the MS to monitor communication channels more frequently and permit switching the MS from Idle state quicker. This shortened Slot Cycle Index (SCI) feature is very useful for time sensitive types of application. Under prior art practice, this slot cycle operates on a multiple of 1.28 second cycles to provide integer multiples of sixteen 80 millisecond slots. The base station controller connected to the MS is the system component that determines whether this shortened slot cycle operation will be utilized for the connected MS, and all of the connected MS will have to use this specified slot cycle. The shortened time slot cycle permits the MS to receive page messages faster and achieve faster call connections. However, the shorter slot cycle results in greater power consumption and shorter operating time on a battery charge.
Not all service options (e.g. call types) require the shorter slot cycle feature. However, under the current method of the base transceiver specifying the shorter slot cycle, all connected network MSs with shortened slot cycle capability must use the shorter slot cycle when the SCI feature is activated at the transceiver. A need exist for a more efficient way to implement the SCI feature setting up the shortened time slot cycle such that only those applications requiring a faster MS response implement the shortened slot cycle.